fix(jakarta): rewrite websocket example to use Jakarta WebSocket API

Replace Jetty-specific JettyWebSocketServlet with standard Jakarta
WebSocket @serverendpoint API. This removes the dependency on Jetty
EE10 websocket server classes.

- Replace WebSocketExample (Jetty annotations) with
  WebSocketExampleEndpoint (Jakarta @serverendpoint)
- Replace JettyWebSocketServlet with HttpServlet that registers
  the endpoint via ServerContainer
- Switch dependencies from Jetty websocket to Jakarta WebSocket API
- Test remains @ignore as Pax Web 11.1.0 OSGi HTTP Whiteboard does
  not support WebSocket endpoint registration via ServerContainer

Author: jbonofre

examples/karaf-websocket-example/pom.xml

@@ -34,15 +34,21 @@
 
     <dependencies>
         <dependency>
-            <groupId>org.eclipse.jetty.ee10.websocket</groupId>
-            <artifactId>jetty-ee10-websocket-jetty-server</artifactId>
-            <version>${jetty.version}</version>
+            <groupId>${servlet.spec.groupId}</groupId>
+            <artifactId>${servlet.spec.artifactId}</artifactId>
+            <version>${servlet.spec.version}</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
-            <groupId>org.eclipse.jetty.websocket</groupId>
-            <artifactId>jetty-websocket-jetty-api</artifactId>
-            <version>${jetty.version}</version>
+            <groupId>jakarta.websocket</groupId>
+            <artifactId>jakarta.websocket-api</artifactId>
+            <version>2.2.0</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>jakarta.websocket</groupId>
+            <artifactId>jakarta.websocket-client-api</artifactId>
+            <version>2.2.0</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
@@ -58,18 +64,6 @@
             <plugin>
                 <groupId>org.apache.felix</groupId>
                 <artifactId>maven-bundle-plugin</artifactId>
-                <configuration>
-                    <instructions>
-                        <Import-Package>
-                            org.osgi.service.component,
-                            org.eclipse.jetty.ee10.websocket.server,
-                            *
-                        </Import-Package>
-                        <Private-Package>
-                            org.apache.karaf.examples.websocket
-                        </Private-Package>
-                    </instructions>
-                </configuration>
             </plugin>
         </plugins>
     </build>

…examples/websocket/WebSocketExample.java …/websocket/WebSocketExampleEndpoint.javaexamples/karaf-websocket-example/src/main/java/org/apache/karaf/examples/websocket/WebSocketExample.java renamed to examples/karaf-websocket-example/src/main/java/org/apache/karaf/examples/websocket/WebSocketExampleEndpoint.java examples/karaf-websocket-example/src/main/java/org/apache/karaf/examples/websocket/WebSocketExample.java renamed to examples/karaf-websocket-example/src/main/java/org/apache/karaf/examples/websocket/WebSocketExampleEndpoint.java

@@ -16,31 +16,30 @@
  */
 package org.apache.karaf.examples.websocket;
 
-import org.eclipse.jetty.websocket.api.Callback;
-import org.eclipse.jetty.websocket.api.Session;
-import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
-import org.eclipse.jetty.websocket.api.annotations.OnWebSocketOpen;
-import org.eclipse.jetty.websocket.api.annotations.WebSocket;
+import jakarta.websocket.OnClose;
+import jakarta.websocket.OnOpen;
+import jakarta.websocket.Session;
+import jakarta.websocket.server.ServerEndpoint;
 
-import java.time.Duration;
+import java.io.IOException;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 
-@WebSocket
-public class WebSocketExample {
+@ServerEndpoint("/example-websocket")
+public class WebSocketExampleEndpoint {
 
     static final Set<Session> sessions = Collections.synchronizedSet(new HashSet<>());
     static volatile boolean notification = false;
 
-    @OnWebSocketOpen
+    @OnOpen
     public void onOpen(Session session) {
-        session.setIdleTimeout(Duration.ZERO);
+        session.setMaxIdleTimeout(0);
         sessions.add(session);
     }
 
-    @OnWebSocketClose
-    public void onClose(Session session, int statusCode, String reason) {
+    @OnClose
+    public void onClose(Session session) {
         sessions.remove(session);
     }
 
@@ -57,15 +56,13 @@ public void run() {
             try {
                 while (notification) {
                     for (Session session : sessions) {
-                        session.sendText("Hello World", Callback.NOOP);
+                        session.getBasicRemote().sendText("Hello World");
                     }
                     Thread.sleep(1000);
                 }
-            } catch (Exception e) {
+            } catch (IOException | InterruptedException e) {
                 e.printStackTrace();
             }
         }
-
     }
-
 }

examples/karaf-websocket-example/src/main/java/org/apache/karaf/examples/websocket/WebsocketExampleServlet.java

@@ -17,35 +17,41 @@
 package org.apache.karaf.examples.websocket;
 
 import jakarta.servlet.Servlet;
-import jakarta.servlet.annotation.WebServlet;
-import org.eclipse.jetty.ee10.websocket.server.JettyWebSocketServlet;
-import org.eclipse.jetty.ee10.websocket.server.JettyWebSocketServletFactory;
-import org.osgi.service.component.annotations.Activate;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.websocket.DeploymentException;
+import jakarta.websocket.server.ServerContainer;
 import org.osgi.service.component.annotations.Component;
 import org.osgi.service.component.annotations.Deactivate;
 
 @Component(
         service = Servlet.class,
-        property = {"osgi.http.whiteboard.servlet.pattern=/example-websocket"}
+        property = {
+                "osgi.http.whiteboard.servlet.pattern=/example-websocket-init",
+                "osgi.http.whiteboard.servlet.init-order=1"
+        }
 )
-@WebServlet(name = "Example WebSocket Servlet", urlPatterns = {"/example-websocket"})
-public class WebsocketExampleServlet extends JettyWebSocketServlet {
+public class WebsocketExampleServlet extends HttpServlet {
 
     @Override
-    protected void configure(JettyWebSocketServletFactory factory) {
-        factory.register(WebSocketExample.class);
-    }
-
-    @Activate
-    public void activate() {
-        WebSocketExample.notification = true;
-        Thread notification = new Thread(new WebSocketExample.NotificationThread(WebSocketExample.sessions));
+    public void init() throws ServletException {
+        super.init();
+        ServerContainer container = (ServerContainer) getServletContext()
+                .getAttribute(ServerContainer.class.getName());
+        if (container != null) {
+            try {
+                container.addEndpoint(WebSocketExampleEndpoint.class);
+            } catch (DeploymentException e) {
+                throw new ServletException("Failed to register WebSocket endpoint", e);
+            }
+        }
+        WebSocketExampleEndpoint.notification = true;
+        Thread notification = new Thread(new WebSocketExampleEndpoint.NotificationThread(WebSocketExampleEndpoint.sessions));
         notification.start();
     }
 
     @Deactivate
     public void deactivate() {
-        WebSocketExample.notification = false;
+        WebSocketExampleEndpoint.notification = false;
     }
-
 }

itests/test/src/test/java/org/apache/karaf/itests/examples/WebSocketExampleTest.java

@@ -39,7 +39,7 @@
 @ExamReactorStrategy(PerClass.class)
 public class WebSocketExampleTest extends BaseTest {
 
-    @Ignore("JettyWebSocketServlet is not compatible with Pax Web 11.1.0 OSGi HTTP Whiteboard websocket upgrade handling")
+    @Ignore("Pax Web 11.1.0 OSGi HTTP Whiteboard does not support WebSocket endpoint registration via ServerContainer")
     @Test(timeout = 60000)
     public void test() throws Exception {
         featureService.installFeature("http-whiteboard");
@@ -50,8 +50,9 @@ public void test() throws Exception {
         Bundle bundle = bundleContext.installBundle("mvn:org.apache.karaf.examples/karaf-websocket-example/" + System.getProperty("karaf.version"));
         bundle.start();
 
+        // Wait for the init servlet to register (which also registers the WebSocket endpoint)
         String httpList = executeCommand("web:servlet-list");
-        while (!httpList.contains("/example-websocket")) {
+        while (!httpList.contains("example-websocket-init")) {
             Thread.sleep(1000);
             httpList = executeCommand("web:servlet-list");
         }